4,4′-Dimethoxy­benzophenone: a triclinic polymorph

Hoong-Kun Fun; S Franklin; Samuel Robinson Jebas; T Balasubramanian

doi:10.1107/S1600536808017315

. 2008 Jun 13;64(Pt 7):o1256. doi: 10.1107/S1600536808017315

4,4′-Dimethoxybenzophenone: a triclinic polymorph

Hoong-Kun Fun ^a,^*, S Franklin ^b, Samuel Robinson Jebas ^a,^‡, T Balasubramanian ^b

PMCID: PMC2961821 PMID: 21202890

Abstract

The title compound, C₁₅H₁₄O₃, has been found to crystallize as a new triclinic polymorph. The asymmetric unit of the present structure, as in the previously reported monoclinic structure [Norment & Karle (1962 ▶). Acta Cryst. 15, 873–878], contains two independent molecules, which differ slightly in the orientations of the two benzene rings. The crystal packing of the triclinic polymorph is stabilized by intermolecular C—H⋯O hydrogen bonds and C—H⋯π interactions.

Related literature

For the monoclinic polymorph of 4,4′-dimethoxybenzophenone, see: Norment & Karle (1962 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₅H₁₄O₃
M _r = 242.26
Triclinic,
a = 9.4296 (2) Å
b = 9.4569 (2) Å
c = 14.7963 (3) Å
α = 76.945 (1)°
β = 78.813 (1)°
γ = 70.670 (1)°
V = 1202.65 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100.0 (1) K
0.50 × 0.19 × 0.16 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.955, T _max = 0.985
26162 measured reflections
6478 independent reflections
4651 reflections with I > 2σ(I))
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.170
S = 1.09
6478 reflections
329 parameters
H-atom parameters constrained
Δρ_max = 0.67 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808017315/ci2608sup1.cif

e-64-o1256-sup1.cif^{(25.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808017315/ci2608Isup2.hkl

e-64-o1256-Isup2.hkl^{(310.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14B—H14E⋯O1Bⁱ	0.96	2.59	3.446 (2)	149
C9B—H9B⋯Cg1ⁱⁱ	0.93	2.84	3.5252 (17)	132
C12B—H12B⋯Cg1ⁱⁱⁱ	0.93	2.78	3.5223 (16)	137
C4B—H4B⋯Cg2^iv	0.93	2.88	3.6301 (18)	138
C9A—H9A⋯Cg3ⁱⁱⁱ	0.93	2.92	3.5723 (16)	128
C12A—H12A⋯Cg3ⁱⁱ	0.93	2.88	3.5651 (16)	132
C4A—H4A⋯Cg4^v	0.93	2.90	3.6376 (17)	138

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) . Cg1, Cg2, Cg3 and Cg4 are the centroids of the C1A–C6A, C8A–C13A, C1B–C13B and C8B–C13B rings, respectively.

Acknowledgments

FHK and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

The crystal structure of the title compound has previously been reported in the monoclinic space group P2₁/a (Norment & Karle, 1962). We report here the structure of a second polymorph which crystallizes in the triclinic space group P1.

The asymmetric unit of the triclinic polymporph contains two crystallographically independent molecules (Fig.1), similar to the monoclinic form. Bond lengths and angles of the molecules agree with each other and show normal values (Allen et al., 1987). The two independent molecules differ slightly in the orientations of the two benzene rings. The dihedral angle formed by C1A-C6A and C8A-C13A rings is 52.12 (8)° and that between C1B-C6B and C8B-C13B planes is 55.73 (7)°. These dihedral angles are comparable to those observed in the monoclinic polymorph.

The crystal packing is stabilized by intermolecular C—H···O hydrogen bonds (Fig.2) and C—H···π interactions.

Experimental

The title compound was purchased from Merck and single crystals suitable for X-ray diffraction studies were obtained by slow evaporation of an ethanol solution.